1. Field of the Invention
The present invention relates to a process of producing homogeneously doped p-conductive semiconductor materials.
2. Prior Art
Doping of semiconductor materials (for example, silicon) is frequently conducted during deposition of the semiconductor material from the gas phase thereof by the thermal decomposition of a gaseous compound yielding the desired semiconductor material onto a heated mandrel. During this process, doping is typically effected by mixing a gaseous compound yielding a desired dopant upon decomposition with the gaseous compound yielding the desired semiconductor material so that the material deposited on the mandrel is a mixture of the semiconductor material and the dopant. Silicon rods produced in this manner are polycrystalline and must be converted into the monocrystalline state by a subsequent zone melt treatment. During this zone melt treatment the dopant concentration often changes in an uncontrollable manner and substantially higher dopant concentrations must be provided in forming the polycrystalline rods to insure that the desired dopant concentration still exists in the ultimately produced monocrystalline rods.
Germanium rods are typically produced via the Czochralski crucible-drawing method wherein a seed crystal is submerged into a germanium melt containing a suitable dopant therein within a crucible and a monocrystalline rod is drawn from the melt by upward movement of the seed crystal. In this process, it is also noted that the dopant evaporates in an uncontrollable manner during the crystal growth process.
Semiconductor bodies composed of A.sup.III B.sup.V compounds, such as gallium arsenide or gallium phosphide, are frequently doped by producing a melt of the compound and a suitable dopant in a crucible or boat and drawing a suitable rod therefrom.
Such known doping processes are time-consuming and inaccurate. Accordingly, electrical components produced from such semiconductor materials are expensive and do not possess optimum electrical characteristics.